The advantages obtained by adopting methods of fabricating pre-hung doors have been known and utilized by the building industry for some time. For example, U.S. Pat. Nos. 3,263,723 and 4,100,611 describe machines for preparing doors for hanging and for fabricating pre-hung doors.
So far as is known, however, such automatic fabrication techniques have not heretofore been extended to the construction of certain parts of the frame that forms the door opening--specifically, the attachment of the doorstop to the doorjamb. It is required that the stop and jamb be in relative longitudinal alignment when attached to one another to provide the appropriate relief between leading edges of the two pieces to allow the door to close properly. Further, the ends of the two pieces must often be placed in adjacent registration. Such alignment, registration and attachment of stops to jambs have been performed manually.
Further, the stops and/or jambs that are used sometimes are warped a small amount, which warpage must be taken into account to ensure proper indexing between the leading edge of the stop and jamb to which it is attached. To perform these tasks manually requires time and expense. Thus, to provide automatic apparatus capable of performing the task of individually aligning and affixing doorstops to doorjambs with relatively precise accuracy can result in a great savings of both time and money.